1. Field of the Invention
The present invention relates to a method and an apparatus for battery control.
2. Description of the Related Art
In a field of personal computers, compact, lightweight, and portable laptop type personal computers have been popular in place of desktop type personal computers.
Most of the laptop type personal computers are driven by batteries or by both the batteries and AC adapters. When an A/C adapter is connected to a computer, the computer is driven by power supplied from the A/C adapter, and the battery is charged by the power. On the other hand, when the A/C adapter is not connected to the computer, the computer is driven by power supplied from the battery. Note that control operations for these power supplies are performed by a power supply controller.
The power supply controller monitors a battery voltage of a battery used for supplying the power. When the monitored battery voltage reaches such a voltage where enough power for operating the computer cannot be supplied, it is determined that the battery is in a low battery state, and the battery is not used any longer. In addition, when the battery voltage reaches a voltage slightly higher than the voltage of the low battery state, the power supply controller generates an alarm to inform a user that the battery capacity is decreased.
Conventionally, when the battery in the low battery state is charged even within a short time, the power supply controller determines that the battery is not in the low battery state, and performs power supply control for the battery.
when the charged battery is used after the battery in the low battery state is charged within a short-time, however, the battery voltage is suddenly decreased to be in the low battery state soon after the use of the battery. As a result, power supply of the computer is turned off without generating the above described alarm. In addition, in a computer having a resume function, the power supply of the computer is turned off before completion of the resume operation. Therefore, the resume function is not sufficiently utilized.
As described above, a demand has arisen for a power supply control apparatus capable of using the battery after sufficient charging of the battery in the low battery state.